To assist in the development of more effective mental health and legal systems, the proposed project will assess and improve current methods for measuring violent behavior. The project includes two phases, with Phase 1 having four primary aims: 1) to conduct a systematic classification and analysis of study designs and findings in violence research, 2) to identify and attempt to resolve methodological issues in the self-report method, 3) to perform secondary analyses of several large data sets on violence in order to estimate the effects of different measurement methods on estimates of the prevalence and correlates of violence, and 4) to develop and test instruments and procedures as an initial step in the research specified in Phase 2. The second phase of the project will utilize the instruments and procedures developed in Phase 1 in an etiological and methodological study of the violent behavior of juvenile and adult mental patients, criminal offenders, and the general population.